Water-soluble phenylenediamine compositions and methods for stabilizing ethylenically unsaturated compounds and monomers

ABSTRACT

Compositions and methods for inhibiting polymerization of ethylenically unsaturated monomers are provided. The compositions include a water-soluble phenylenediamine composition.

FIELD OF THE INVENTION

[0001] The present invention relates to water-soluble phenylenediaminecompositions and methods for inhibiting polymerization of ethylenicallyunsaturated hydrocarbons.

BACKGROUND OF THE RELATED TECHNOLOGY

[0002] During the refining process, hydrocarbon streams are frequentlyexposed to elevated temperatures, which can lead to prematurepolymerization of the desired monomer. The premature polymerizationresults in reduction of the amount of the desired monomer end-productsas well as a loss in efficiency caused by fouling and deposit formationwithin the processing equipment.

[0003] In order to reduce or prevent polymer formation, stabilizing orinhibitor compositions have been introduced into the hydrocarbon streamat or upstream of a location where polymerization is likely to occur,such as where distillation is performed.

[0004] Phenylenediamines (PDA's) are widely used as antioxidants andpolymerization inhibitors. However, their use is limited to hydrocarbonstreams where the PDA is soluble. A number of patents relate to the useof various PDA's, combinations of different PDA's and combinations ofPDA's with other inhibitors to stabilize hydrocarbon fluids.

[0005] Among these patents is U.S. Pat. No. 6,200,461 to Eldin whichdescribes methods and compositions for inhibiting the polymerization ofethylenically unsaturated hydrocarbons under both processing and storageconditions by the addition of combinations of aminophenol compounds andeither PDA or hydroxylamine. Other combinations have also been used.These include inhibitor combinations containing a PDA with an oximecompound and a hydroxylamine as shown in U.S. Pat. No. 5,489,718 toArhancet. Other examples include the combination of a PDA and ahydroxylamine as shown in U.S. Pat. No. 5,396,004 to Arhancet and a PDAwith a hydroxytoluene compound as shown in U.S. Pat. No. 5,416,258 toArhancet et al.

[0006] Examples of specific PDA compounds may be found in U.S. Pat. No.4,929,778 to Roling which describes compositions including a PDAcompound which has at least one N—H bond and a hindered phenol usefulfor inhibiting the polymerization of styrene during elevated temperatureprocessing, storage and shipment. U.S. Pat. No. 4,774,374 to Abruscatoet al. discloses an oxygenated species formed by the reaction of oxygenand an N-aryl-N′-alkyl-p-phenylenediamine.

[0007] While each of these references provides compositions and methodsthat reduce premature polymerization of ethylenically unsaturatedmonomers, they are generally limited to hydrocarbon processing andstorage where they are soluble, which does not include where water ispresent. Therefore, the currently available PDA inhibitors do notadequately address the concerns of the prevention of prematurepolymerization of a monomers with water-solubility, where a water phaseis present.

[0008] Therefore, it would be desirable to provide a water-solublecomposition for the reducing and or preventing the polymerization ofethylenically unsaturated monomers. Desirably, the composition willinclude a water-soluble phenylenediamine composition which acts as anantioxidant/free-radical polymerization inhibitor.

SUMMARY OF THE INVENTION

[0009] The present invention provides a water-soluble phenylenediaminecomposition which also functions as an antioxidant/free-radicalpolymerization inhibitor. The compounds are of the following formula:

[0010] wherein at least one of R¹, R², and R³ is

[0011] R¹, R² and R³ are independently selected from H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶, —N—(R⁷)(R⁸), aryl, and

[0012] R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, O, S, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl;

[0013] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and—N(R⁷)(R⁸); and

[0014] R⁶, R⁷ and R⁸ are independently selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo. Desirably, the compound correspondsthe following formula:

[0015] The compounds of formula (I), above, may be added to acomposition including an ethylenically unsaturated monomer to produce acomposition resistant to polymerization. The addition of thewater-soluble phenylenediamine composition of the present invention tothe monomer composition may occur during synthesis or processing orstorage of the composition.

[0016] The compounds of the present invention include a reaction productof a phenylenediamine compound of the following formula:

[0017] wherein at least one of R¹, R² and R³ is H;

[0018] R¹, R² and R³ are independently selected from the groupconsisting of, alkyl, hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶,—N—(R⁷)(R⁸), and aryl;

[0019] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN₁—NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸);and

[0020] R⁶, R⁷ and R⁸ are independently selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo,

[0021] with a heterocylic compound of the following formula:

[0022] wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl.

[0023] Another aspect of the present invention provides a method ofpreparing a water-soluble phenylenediamine composition including thestep of reacting a phenylenediamine compound of the following formula:

[0024] wherein at least one of R¹, R² and R³ is H and

[0025] R¹, R² and R³ are independently selected from the groupconsisting of, alkyl, hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶,—N—(R⁷)(R⁸), and aryl;

[0026] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and—N(R⁷)(R⁸); and

[0027] R⁶, R⁷ and R⁸ are independently selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo,

[0028] with a heterocylic compound of the following formula:

[0029] wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl. Desirably, thephenylenediamine compound is 1,4-phenylenediamine.

[0030] A further aspect of the present invention provides a method ofreducing or inhibiting fouling and deposit formation during hydrocarbonprocessing including the step of administering an effective amount ofone or more water-soluble compounds of the following formula to ahydrocarbon stream at or upstream of a location where said foulingand/or said deposit formation may occur:

[0031] wherein at least one of R¹, R², and R³ is

[0032] R¹, R² and R³ are independently selected from H, C₁-C₁₈ alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), aryl, and

[0033] R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl;

[0034] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and—N(R⁷)(R⁸);

[0035] R⁶, R⁷ and R⁸ are independently selected form the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo; and wherein

[0036] said composition is water-soluble.

DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention includes compounds of the formula:

[0038] wherein the NHR³ group may be present in any of the ortho, para,and meta positions,

[0039] at least one of R¹, R², and R³ is

[0040] R¹, R² and R³ are independently selected from H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶, —N—(R⁷)(R⁸), aryl, and

[0041] R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, O, S, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl;

[0042] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and—N(R⁷)(R⁸); and

[0043] R⁶, R⁷ and R⁸ are independently selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo. Desirably, the second amine group isin the para position, corresponding to the following formula:

[0044] The term “alkyl” is meant to include substituted orunsubstituted, straight or branched chain saturated hydrocarbon groups,desirably having 1 to 20 carbons in the main chain. Examples ofunsubstituted groups include methyl, ethyl, propyl, isopropyl, n-butyl,t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethyl pentyl,octyl, 2,2,4-trimethylpentyl, nonyl, decyl, undecyl, dodecyl, and thelike. Substituents may include halogen, hydroxy, or aryl groups.

[0045] The term “hydroxyalkyl” is meant to include an alkyl group asdescribed above with at least one hydroxy group substituent.

[0046] The term “alkenyl” is meant to include substituted orunsubstituted, straight or branched chain hydrocarbon groups includingat least one carbon to carbon double bond in the chain, and desirablyincluding 2 to 10 carbons in the normal chain. Examples of suchunsubstituted alkenyl groups include ethenyl, propenyl, isobutenyl,butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, and thelike. Substituents may include those as described above.

[0047] The term “alkynyl”, is meant to include substituted orunsubstituted, straight and branched chain hydrocarbon groups includingat least one carbon to carbon triple bond in the chain, and preferablyhaving 2 to 10 carbons in the normal chain. Examples of suchunsubstituted groups include ethynyl, propynyl, butynyl, pentynyl,hexynyl, heptynyl, octynyl, nonynyl, decynyl, and the like. Substituentsmay include those as described above.

[0048] The term “cycloalkyl” is meant to include substituted orunsubstituted, saturated cyclic hydrocarbon ring systems, preferablycontaining 1 to 3 rings and 3 to 7 carbons per ring. Exemplaryunsubstituted such groups include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl, andadamantyl. Exemplary substituents include one or more alkyl groups asdescribed above, or one or more groups described above as alkylsubstituents.

[0049] The term “cycloalkenyl” is meant to include hydrocarbon ringsystems which may be substituted or unsubstituted as described above forcycloalkyl, further containing at least one carbon to carbon double bondforming a partially unsaturated ring. These may also includesubstituents as described above.

[0050] The terms “heterocyclo” or “heterocyclic” are meant to includesubstituted or unsubstituted, fully saturated or unsaturated, aromaticor non-aromatic cyclic groups having at least one heteroatom (such as N,O, and S) in at least one ring, desirably monocyclic or bicyclic groupshaving 3-6 atoms in each ring. The heterocyclo group may be bondedthrough any carbon or heteroatom of the ring system. Examples ofheterocyclic groups include, without limitation, thienyl, furyl,pyrrolyl, pyridyl, imidazolyl, pyrrolidinyl, piperidinyl, azepinyl,indolyl, isoindolyl, quinolinyl, isoquinolinyl, benzothiazolyl,benzoxazolyl, benzimidazolyl, benzoxadiazolyl, and benzofurazanyl. Thesemay also include substituents as described above.

[0051] The term “aryl” is meant to include substituted or unsubstitutedmonocyclic, bicyclic or tricyclic aromatic groups, desirably includingone or two rings which contain only carbon ring atoms and 6 to 12 ringcarbons. The term “aryl” can also refer to an aryl group fused to amonocyclic cycloalkyl or monocyclic heterocycle in which the point(s) ofattachment is/are on the aromatic portion. Examples of aryl groupsinclude phenyl, biphenyl, and naphthyl. Aryl rings fused to cycloalkylsare include indanyl, indenyl, and tetrahydronaphthyl. Examples of arylgroups fused to heterocyclic groups include 2,3-dihydrobenzofuranyl,benzopyranyl, 1,4-benzodioxanyl, and the like. Substituents may includethose as described above as well as nitro groups.

[0052] The water-soluble phenylenediamine compounds of the presentinvention may be formed by the reaction of a phenylenediamine compoundof the following formula:

[0053] wherein at least one of R¹, R² and R³ is H;

[0054] R¹, R² and R³ are independently selected from the groupconsisting of, alkyl, hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶,—N—(R⁷)(R⁸), and aryl;

[0055] Z comprises one or more substituents selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl, heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and—N(R⁷)(R⁸); and

[0056] R⁶, R⁷ and R⁸ are independently selected from the groupconsisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heterocyclo,

[0057] with a heterocylic compound of the following formula:

[0058] wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl. Desirably, theheterocyclic compound is propylene oxide or butylene oxide.

[0059] This reaction produces a mixture of reaction products that may beseparated by any of a variety of means known in the art, includingchromatography. For example, the reaction of 1,4-phenylenediamine withthe substituted heterocyclic compound may produce a mixture of fivedifferent products as shown in the following reaction scheme:

[0060] Similarly, where the phenylenediamine starting material includesa non-hydrogen substitution, the products of the reaction with thesubstituted heterocyclic compound are shown by the reaction scheme asshown below.

[0061] The reaction of 1,4-phenylenediamine with propylene oxide willalso produce a mixture of products which includeN,N′-dihydroxypropylphenylenediamine,N,N-dihydroxypropylphenylenediamine, N-hydroxypropylphenylenediamine,N,N,N′-trihydroxypropylphenylenediamine, andN,N,N′,N′-tetrahydryoxypropylphenylenediamine.

[0062] The phenylenediamine compounds of the present invention areuseful as antioxidant/free-radical polymerization inhibitors. In otherwords, they are useful to stabilize hydrocarbon compositions includingethylenically unsaturated monomers by inhibiting polymerization. Theyare useful as inhibitors under both process and storage conditionsincluding where the monomers are subjected to elevated temperatures, forexample up to about 125° C.

[0063] The water-soluble phenylenediamine compositions are useful with avariety of ethylenically unsaturated monomers. These include, but arenot limited to vinyl aromatic compounds such as styrene, substitutedstyrene, divinylbenzene, vinyl toluene, and vinyl naphthalene, and otherethylenically unsaturated monomers such as acrylic acid, alkylacrylates, acrylonitrile, butadiene, dicyclopentadiene, cyanoacrylates,isoprene, and propylene.

[0064] For the methods of the present invention, the usefulwater-soluble phenylenediamine compositions will retain at least one“—NH” group for effective polymerization inhibition. The effectiveamount of the water-soluble phenylenediamine composition having at leastone “—NH” group used in the methods of the present invention as apolymerization inhibitor is that amount which is sufficient to affectinhibition of polymerization and will vary according to the conditionsunder which the monomer is synthesized, processed, and/or stored. Thereare several factors that will affect the amount of inhibitor that isrequired. Factors that will require an increase in the amount ofinhibitor are increased monomer concentration and increased temperature.

[0065] Generally, an effective concentration of the water-solublephenylenediamine compositions of the present invention will range fromabout 0.5 ppm to about 2000 ppm, more desirably from about 1 ppm toabout 50 ppm. The compositions may be used in many hydrocarbonprocessing steps where premature polymerization is likely to occurincluding hydrocarbon cracking processes, preheating, distillation,hydrogenation, extraction, etc. The water-soluble phenylenediaminecomposition may be added at a location upstream of these processlocations.

[0066] The water-soluble phenylenediamine compositions may be added to awater stream, hydrocarbon stream or to a monomer composition alone, orafter first being premixed with a solvent. Where a premix of thewater-soluble phenylenediamine composition is desired, it may be firstcombined with a solvent such as water or an organic solvent including,but not limited to methanol, ethanol, acetone, pyridine, nitrobenzene,n-hexadecane, n-hexane, methylene chloride, dimethyl sulphoxide,chloroform, carbon tetrachloride, benzene, glycols, esters and ethers.

[0067] Other inhibitors or antifoulants known in the art may be combinedwith the water-soluble phenylenediamine compounds of the presentinvention. These may include other phenylenediamines, hydroxylamines,nitroxides, and hindered phenols. When a compositions containing anadditional phenylenediamine composition is desired, the additionalphenylenediamine may correspond to the following formula:

[0068] wherein R^(a), R^(b) and R^(c) are independently selected fromthe group consisting of H, C₁-C₁₈ alkyl, hydroxyalkyl, —O—R⁶, —S—R⁶,—N—(R⁷)(R⁸), and aryl.

[0069] The water-soluble phenylenediamine compositions of the presentinvention have a wider variety of uses as compared to conventionalphenylenediamine inhibitors. For example, during processing ofacrylonitrile, there is contact with water and consequent fouling anddeposit formation in the water sections. A phenylenediamine compositionthat is not water-soluble will not be effective as an inhibitor in thissituation.

[0070] PDA's such as N-(1,4-dimethylpentyl)-N′-phenyl-p-phenylenediamineand N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine are not misciblewith water. Instead, when they are added to water, they separate,forming two distinct layers, a PDA layer and a water layer. However, thePDA's of the present invention are completely miscible with water. Whenthey are added to water, the PDA's of the present invention do not forma separate layer, i.e., a partition between the aqueous and hydrocarbonphases where it provides vinyl monomer free radical polymerizationinhibition.

[0071] The features and advantages of the present invention are morefully shown by the following examples which are provided for purposes ofillustration, and are not to be construed as limiting the invention inany way.

EXAMPLES

[0072] Acrylonitrile was chosen to represent reactive vinyl monomers.The water-soluble phenylenediamines (PDA's) of the present inventionwere tested in acrylonitrile. Comparative testing was also performedusing conventional polymerization inhibitors. The comparative inhibitorcompositions are shown in TABLE 1, while the inventive inhibitorcompositions which were tested are shown in TABLE 2. The parenthesisafter the inhibitor names indicates the weight ratio of two or moreinhibitors in the composition. TABLE 1 Comparative InhibitorCompositions Composition Inhibitor(s) A Blank B Hydroquinone CN-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine D BenzoquinonediimideE Benzoquinonediimide/Hydroquinone (1:1) FHydroquinone/N-(1,3-dimethylbutyl)-N-phenyl-p- phenylenediamine (1:1) GHydroquinone/N-(1,4-dimethylpentyl)-N′-phenyl-p- phenylenediamine (1:1)H N-(1,4-dimethylpentyl)-N′-phenyl-p- phenylenediamine

[0073] TABLE 2 Inventive Inhibitor Compositions Composition Inhibitor(s)I N,N,N′,N′-Tetrahydroxypropylphenylenediamine JN-hydroxypropylphenylenediamine and N,N′-dihydroxypropylphenylenediamine (reaction mixture) KN-hydroxypropylphenylenediamine and N,N′-dihydroxypropylphenylenediamine (reaction mixture)/ Hydroquinone (1:1) LN-hydroxypropylphenylenediamine and N,N′-dihydroxypropylphenylenediamine (reaction mixture)/ Benzoquinonediimide(1:1)

[0074] For each of the experiments, acrylonitrile was heated under aninert atmosphere in glass tubes. A single inhibitor composition (A-L)was added to each tube. In the first experiment, tubes containingacrylonitrile were dosed with 2 ppm of various inhibitors and wereheated at 110° C.

[0075] For the second experiment, 35 ppm azobisobutyronitrile (AIBN), afree radical polymerization initiator, was also added to each tube tosimulate conditions where free radical concentrations are relativelyhigh. The second experiment was conducted at 66° C.

[0076] For each experiment, the performance of the inhibitor performancewas judged by the length of the induction time for polymerization, i.e.,the formation of visible polymer, as the reaction mixture turned turbidand white polyacrylonitrile started to deposit. The results of bothexperiments are shown in TABLE 3, below. TABLE 3 Results ofAcrylonitrile Study Induction Time to Polymerization Experiment 2 (withpolymerization initiator) Composition Experiment 1 (hours) (minutes) A 1 15 B 2.2 132 C 106 n/a D 508 n/a E 528 160 F n/a 183 G n/a 195 H n/a230 I 4  49 J 106 290 K 168 n/a L 278 n/a

[0077] As can be seen from TABLE 3, the inventive compositions J, K andL performed better than the comparative compositions that included theknown polymerization inhibitors hydroquinone,N-(1,4-dimethylpentyl)-N′-phenyl-p-phenylenediamine, andN-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine. In addition,inventive composition J has the advantage of being water-soluble whichincreases the variety of potential uses.

[0078] While there have been described what are presently believed to bethe preferred embodiments of the invention, those skilled in the artwill realize that changes and modifications may be made thereto withoutdeparting from the spirit of the invention, and it is intended toinclude all such changes and modifications as fall within the true scopeof the invention.

What is claimed is:
 1. A composition comprising one or more compounds ofthe following formula:

wherein at least one of R¹, R², and R³ is

R¹, R² and R³ are independently selected from H, alkyl, hydroxyalkyl,—O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶, —N—(R⁷)(R⁸), aryl, and

R⁵ is selected from the group consisting of H, alkyl, hydroxyalkyl, O,S, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl; Z comprises one or moresubstituents selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heterocyclo, —CN,—NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸); and R⁶, R⁷ and R⁸ are independentlyselected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkenyl, aryl and heterocyclo.
 2. The composition ofclaim 1, wherein at least one of said compounds corresponds to thefollowing formula:


3. The composition of claim 1, wherein said composition iswater-soluble.
 4. The composition of claim 1, further comprising asolvent.
 5. The composition of claim 1, further comprising a solventselected from the group consisting of water and an organic solvent. 6.The composition of claim 1, further comprising a second polymerizationinhibitor composition.
 7. The composition of claim 6, wherein saidsecond polymerization inhibitor composition is a phenylenediamine of thefollowing formula:

wherein R^(a), R^(b) and R^(c) are independently selected from the groupconsisting of H, C₁-C₁₈ alkyl, hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸),and aryl.
 8. The composition of claim 1, wherein said compositioncomprises a compound of the following formula:


9. The composition of claim 1, wherein said composition comprises atleast one of the following compounds:


10. The composition of claim 1, wherein said composition comprises atleast one of the following compounds:


11. A composition resistant to polymerization comprising: (a) anethylenically unsaturated monomer, and (b) one or more water-solublecompounds of the following formula:

wherein at least one of R¹, R², and R³ is

R¹, R² and R³ are independently selected from H, C₁-C₁₈ alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), aryl, and

R⁵ is selected from the group consisting of H, alkyl, hydroxyalkyl,—O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl; Z comprises one or moresubstituents selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heterocyclo, —CN,—NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸); R⁶, R⁷ and R⁸ are independentlyselected form the group consisting of hydrogen, alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkenyl, aryl and heterocyclo; and wherein saidcomposition is water-soluble.
 12. The composition of claim 11, furthercomprising a solvent.
 13. A method of preparing a water-solublephenylenediamine composition comprising the step of reacting aphenylenediamine compound of the following formula:

wherein at least one of R¹, R² and R³ is H and R¹, R² and R³ areindependently selected from the group consisting of, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶, —N—(R⁷)(R⁸), and aryl; Zcomprises one or more substituents selected from the group consisting ofhydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl,heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸); and R⁶, R⁷ and R⁸are independently selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclo, with aheterocyclic compound of the following formula:

wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl.
 14. A method ofpreparing a water-soluble phenylenediamine composition comprising thestep of reacting 1,4-phenylenediamine with a heterocyclic compound ofthe following formula:

wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl.
 15. The method ofclaim 14, wherein said heterocyclic compound comprises a member selectedfrom the group consisting of propylene oxide and butylene oxide.
 16. Themethod of claim 14, wherein said water-soluble phenylenediamine retainsat least one unsubstituted “—NH” group.
 17. A method of reducing orinhibiting fouling and deposit formation during hydrocarbon processingcomprising the step of administering to a hydrocarbon stream at orupstream of a location where said fouling and/or said deposit formationmay occur an effective amount of one or more water-soluble compounds ofthe following formula:

wherein at least one of R¹, R², and R³ is

R¹, R² and R³ are independently selected from H, C₁-C₁₈ alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), aryl, and

R⁵ is selected from the group consisting of H, alkyl, hydroxyalkyl,—O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl; Z comprises one or moresubstituents selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heterocyclo, —CN,—NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸); R⁶, R⁷ and R⁸ are independentlyselected form the group consisting of hydrogen, alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkenyl, aryl and heterocyclo; and wherein saidcomposition is water-soluble.
 18. The method of claim 17, furthercomprising the step of mixing said water-soluble compounds with asolvent prior to said administering.
 19. A reaction product of aphenylenediamine compound of the following formula:

wherein at least one of R¹, R² and R³ is H; R¹, R² and R³ areindependently selected from the group consisting of, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —C(O)R⁶, —C(S)R⁶, —N—(R⁷)(R⁸), and aryl; Zcomprises one or more substituents selected from the group consisting ofhydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl,heterocyclo, —CN, —NO₂, —O—R⁶, —S—R⁶, and —N(R⁷)(R⁸); and R⁶, R⁷ and R⁸are independently selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl and heterocyclo, with aheterocylic compound of the following formula:

wherein R⁵ is selected from the group consisting of H, alkyl,hydroxyalkyl, —O—R⁶, —S—R⁶, —N—(R⁷)(R⁸), and aryl.
 20. The reactionproduct of claim 19, wherein said phenylenediamine compound is1,4-phenylenediamine.
 21. The product of claim 19, wherein said productretains at least one unsubstituted “—NH” group.